title: Electrical stimulation of somatic afferent nerves in the foot increases bladder capacity in healthy human subjects.
abstract: OBJECTIVE
  We determined whether electrical stimulation of somatic afferent nerves in the foot could delay bladder filling sensations and increase bladder capacity in healthy humans without overactive bladder.
  
  
  METHODS
  Eight subjects underwent 90-minute foot stimulation using skin surface electrodes connected to a transcutaneous electrical nerve stimulator. The electrodes were attached to the bottom of the foot. Subjects completed a 3-day voiding diary, during which foot stimulation was applied on day 2. Stimulation parameters were pulse frequency 5 Hz, rectangular waveform pulse width 0.2 milliseconds and intensity 2 to 6 times the minimal stimulation current necessary to induce toe twitch. Stimulation intensity was set by each subject to a maximal level without causing discomfort. Subjects were provided with 500 to 1,000 ml of water to drink during stimulation.
  
  
  RESULTS
  Average ± SE volume per void was 350 ± 22 ml during the 24 hours before foot stimulation. This voided volume increased to a mean of 547 ± 52 ml for up to 5 hours after stimulation (p <0.01). Average voided volume returned to 363 ± 21 ml within 36 hours after stimulation. There were no adverse events.
  
  
  CONCLUSIONS
  Foot stimulation can delay bladder filling sensations and significantly increase bladder capacity in healthy humans without overactive bladder. Although the study group was small, our results support moving forward with clinical trials of foot neuromodulation in patients with overactive bladder.
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Mang L
authors.initials: ML
authors.lastname: Chen
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Chermansky
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Bing
authors.initials: B
authors.lastname: Shen
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: James R
authors.initials: JR
authors.lastname: Roppolo
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: William C
authors.initials: WC
authors.lastname: de Groat
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania. Electronic address: cftai@pitt.edu.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Tai
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005528:Foot / Q000294:innervation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009475:Neurons, Afferent / Q000502:physiology*; D001743:Urinary Bladder / Q000294:innervation / Q000502:physiology*; D014554:Urination
keywords: afferent; electrical stimulation; foot; neurons; urinary bladder; urination